What is the initial treatment for a patient presenting with acute pericarditis?

Initial Treatment for Acute Pericarditis

First-line therapy for acute pericarditis consists of aspirin (750-1000 mg every 8 hours) or ibuprofen (600 mg every 8 hours) combined with colchicine (0.5 mg once daily if <70 kg or twice daily if ≥70 kg) for all patients without contraindications. 1

First-Line Pharmacologic Therapy

NSAIDs/Aspirin

• Aspirin 750-1000 mg every 8 hours OR ibuprofen 600 mg every 8 hours should be initiated immediately with gastroprotection (proton pump inhibitor) 1, 2
• Treatment duration is typically 1-2 weeks, but should continue until complete symptom resolution and C-reactive protein (CRP) normalization 1, 2, 3
• Tapering is mandatory: decrease aspirin by 250-500 mg every 1-2 weeks or ibuprofen by 200-400 mg every 1-2 weeks 1
• Choose aspirin over other NSAIDs when antiplatelet therapy is already indicated for other conditions 1

Colchicine (Mandatory Addition)

• Colchicine must be added to NSAID therapy as first-line treatment, not reserved for recurrences 1, 2
• Weight-adjusted dosing: 0.5 mg once daily if <70 kg; 0.5 mg twice daily if ≥70 kg 1, 2
• Duration is 3 months to prevent recurrences 1, 2
• Colchicine reduces recurrence rates from 37.5% to 16.7% (absolute risk reduction 20.8%) 3
• Tapering is not mandatory but may be considered (0.5 mg every other day for <70 kg or 0.5 mg once daily for ≥70 kg in final weeks) 1

Risk Stratification and Triage

High-Risk Features Requiring Hospital Admission 1

• Major risk factors: fever >38°C (>100.4°F), subacute onset over several days, large pericardial effusion (>20 mm diastolic echo-free space), cardiac tamponade, or failure to respond to NSAIDs within 7 days 1
• Minor risk factors: myopericarditis, immunosuppression, trauma, or oral anticoagulant therapy 1
• Any patient with at least one major or minor risk factor requires hospital admission and etiologic workup 1

Low-Risk Patients

• Patients without high-risk features can be managed as outpatients with NSAID plus colchicine therapy 1, 2
• Outpatient follow-up should monitor symptom resolution and CRP normalization 1, 2

Monitoring Treatment Response

• CRP should be checked to guide treatment duration and assess therapeutic response 1, 2
• Continue therapy until both symptoms resolve AND CRP normalizes 1, 2, 3
• Only begin tapering after achieving complete remission 1
• Premature discontinuation before CRP normalization is a common cause of recurrence 2, 4

Second-Line Therapy (Corticosteroids)

Corticosteroids are NOT first-line therapy and should only be used when NSAIDs/colchicine are contraindicated or have failed 1, 2

When to Consider Corticosteroids

• Contraindication to both aspirin/NSAIDs and colchicine 1, 2
• Failure of first-line therapy after adequate trial 1, 2
• Specific indications: autoimmune disease, pregnancy beyond 20 weeks, or uremic pericarditis 1, 5
• Infectious causes must be excluded before starting corticosteroids 1, 2

Corticosteroid Dosing

• Use low-dose corticosteroids only: prednisone 0.2-0.5 mg/kg/day (NOT high-dose 1.0 mg/kg/day) 1, 2, 4
• Maintain initial dose until symptom resolution and CRP normalization, then taper 1
• Avoid corticosteroids as first-line because they increase risk of chronic disease evolution, recurrence, and drug dependence 1, 4

Activity Restriction

Non-Athletes

• Restrict physical activity beyond ordinary sedentary life until symptoms resolve and CRP, ECG, and echocardiogram normalize 1, 2
• This typically requires several weeks 1

Athletes

• Minimum 3-month restriction from competitive sports after initial onset, regardless of symptom resolution 1, 2
• Return to competition only after complete symptom resolution AND normalization of CRP, ECG, and echocardiogram 1

Critical Pitfalls to Avoid

Common Treatment Errors

• Starting corticosteroids as first-line therapy: increases recurrence risk from 15-30% to 50% and promotes chronicity 1, 4
• Inadequate treatment duration of the first episode: most common cause of recurrence 1, 2, 4
• Omitting colchicine from initial therapy: without colchicine, recurrence rates are 15-30% after first episode and increase to 50% after first recurrence 1, 3
• Tapering before CRP normalization: leads to symptom persistence and recurrence 1, 2
• Premature return to exercise: particularly dangerous for athletes 1

Prognostic Considerations

• Most patients with idiopathic/viral pericarditis have excellent prognosis 1, 3
• Constrictive pericarditis risk: <1% for idiopathic/viral, 2-5% for autoimmune/neoplastic, 20-30% for bacterial (especially tuberculosis) 1, 2, 4
• Cardiac tamponade is rare (<3%) in idiopathic pericarditis but more common with specific etiologies (malignancy, tuberculosis, purulent) 1, 3

Special Populations

Renal Impairment

• Colchicine is contraindicated in severe renal impairment (CrCl <30 mL/min) 2
• For moderate impairment (CrCl 30-50 mL/min), use standard dose with close toxicity monitoring 2
• For dialysis patients, maximum dose is 0.3 mg twice weekly 2
• Consider low-dose corticosteroids as alternative if NSAIDs/colchicine contraindicated by renal dysfunction 2

Autoimmune Disease (e.g., Lupus)

• Same first-line therapy: NSAIDs plus colchicine 4
• Intermediate risk (2-5%) for developing constrictive pericarditis compared to <1% for idiopathic causes 1, 4
• May require treatment of underlying systemic disease activity 4